It is frequently necessary, for a variety of reasons, to open a locked door, particularly a door locked with a mortise cylinder-type lock, without the benefit of the key designed for that lock. For example, the occupant of the premises may have lost, or temporarily misplaced, the key which operates that mortise cylinder-type lock, but still requires the ability to gain access to the premises. In some circumstances, the occupant of the premises is not available, but public safety officials, such as the police, require access under appropriate authority. In these cases, as well as others, it is necessary to be able to open the door without access to the proper key and, generally, it is desired that this access be accomplished without damage to the door structure or the mortise cylinder counterpart which is inside the door.
In recent years, many locks, such as the Medeco.RTM., have been developed which are extremely difficult to open without the necessary key. Some of these security type locks, for example, are provided with case hardened steel in various portions of the lock body to inhibit defeating the lock. Even these locks, however, can be opened in the absence of the proper key, employing the device of the present invention.
The cylinder material of cylinder-type locks, because of the requirements in formation of the lock for normal operation, can be drilled out, even if a masonry type bit is required for this drilling operation. Heretofore, however, no tool has been available to allow opening of the lock, except for lock picks which are, for the most part, ineffective on high security mortise cylinder locks. Thus, though partial access might be gained to security type, cylinder locks, the door could still not be opened without actual damage to the door, mortise cylinder lock counterpart within the door, or the door jamb.
While it remains important to prevent unauthorized access to an enclosure when the proper key is not available, it is still important for authorized personnel, including licensed locksmiths and public safety officials to be able to gain access when necessary, and without unnecessary destruction of property. It is to that end that the present invention is directed.
The prior art has dealt with means for decoding the tumbler sequence in a circular key lock, such as in Hughes, U.S. Pat. No. 4,094,176, but such a method is not effective in all high security type mortise locks. Further, though L-shaped insertion devices have been described as, for example, in U.S. Pat. No. 3,990,301, Smith, these are ineffective for opening a lock from which the plug has been drilled. The device in the Smith Patent, for example, is extremely complex and bulky. Thus, it is not adapted for insertion into the 1/4" hole formed by drilling of the plug of a mortise-type cylinder lock.